1. Field of the Invention:
The present invention provides a metabolic catheter which is designed to achieve immediate mixing of two fluids during withdrawal of a first fluid. More specifically the present invention allows the simultaneous removal of body fluids from organs and the immediate addition of stop solution at the catheter tip to the body fluid to prevent degradation of the metabolite to be measured.
2. Prior Art:
U.S. Pat. No. 4,601,697 describes an indwelling double bore catheter which has a small mixing chamber at the distal end of the double bores. This allows for a better dilution and sampling of blood.
U.S. Pat. No. 4,364,922 describes a method of diagnosing atrioventricular conduction block caused by ischemia of the heart by measuring the time delay between the arterial and ventricular excitation before and after the administration of an adenosine antagonist.
U.S. Pat. No. 4,512,348 shows an invention which continuously and automatically monitors the concentration of specific blood constituents. The invention uses a double current catheter inserted into a vein.
U.S. Pat. No. 4,265,249 shows a semi-permeable filter catheter for taking samples from within fluid carrying members. A rinsing fluid is injected into this catheter.
Ontyd and Schrader in the article entitled "Measurement of Adenosine, Inosine and Hypoxanthine in Human Plasma" found in the Journal of Chromatography, 307, 404-409 (1981), which is printed in the Netherlands, disclose the use of an ice-cold "stopping" solution which consists of dipyridamole, NaCl, KCl, NaHCO.sub.3, glucose, CaCl.sub.2, Na.sub.2 HPO.sub.4 and NaH.sub.2 PO.sub.4 to prevent the degradation of adenosine. In addition this article describes a specially developed syringe system, where the "collecting" syringe was mechanically coupled with the syringe containing the "stopping" solution so that when the blood was drawn by pulling out the collecting syringe's plunger, the plunger of the "stopping" solution syringe was pushed in forcing the "stopping" solution to immediately mix with this aspirated blood in the collecting syringe's chamber. Therefore, this device achieved mixing only within the syringe device, whereas the current application achieves mixing at the sampling site, allowing measurement of metabolites from internal organs. This article also describes that due to the dimensions of the syringes a constant mixing ratio of 1:1 was achieved.